In recent years, LCD televisions that are provided with a 3D (three-dimensional) image processing function that stereoscopically displays an image and smartphones with a portable telephone function and portable information terminal function have come to be known. Methods of stereoscopically displaying an image include a method that shows a stereoscopic image by using polarized glasses, and a method that shows a stereoscopic image by unaided vision without using polarized glasses. The latter method that shows a stereoscopic image by unaided vision uses the parallax barrier method that stereoscopically shows an image by utilizing the parallax between the left eye and the right eye. That is to say, this parallax barrier method enables stereoscopic vision of an image by creating minute gaps by a liquid crystal, and separately showing different images to the left and right eyes.
As a 3D stereoscopic image display device of this kind of parallax barrier method, there is known a device that includes a user interface in which operation detection is possible at the image formation position of a stereoscopic image (for example, refer to Patent Document 1). According to this technology, for example, as the user interface, four operation buttons (start buttons) are stereoscopically displayed at the same 3D display height (Hf). Among the four start buttons “START A”, “START B”, “START C”, “START D” that are stereoscopically displayed, when the “START C” button is operated, at that point in time, a sensor response (object judgment) immediately occurs. Also, immediately, only the “START C” button that has been operated is changed to a two-dimensional (2D) display state in which the 3D display height Hf=0. For that reason, even with stereoscopic images, the operator immediately understands the operation result at the time of operation in the same manner as the case of ordinary two-dimensional images. For that reason, operational discomfort is resolved.
The quality of this kind of operation responsiveness is attained by matching sensor response positions to the image formation positions of stereoscopic images separated from the outer surface of the liquid crystal panel (that is to say, the 3D display height Hf). At this time, the image state of the three start buttons “START A”, “START B”, “START C” other than the start button “START C” remain as they are, and the image state of the operated start button “START C” is switched. That is to say, since the image state of the three start buttons “START A”, “START B”, “START C” remains at the 3D display height Hf, the parallax barrier is maintained as is. On the other hand, only the image state of the start button “START C” switches to 2D. In order to realize this kind of image display phenomenon, it is necessary for a stereoscopic image display device to be constituted so that a desired requirement relating to the aforementioned sensitivity property (that is to say, the phenomenon of a start button immediately switching to the 2D display state by operation detection of the start buttons at the 3D image formation positions) is satisfied.
As other related art, there is disclosed the art of an image display system that can change the protrusion amount of a partial region of a stereoscopic image (for example, refer to Patent Document 2). That is to say, ordinarily, it is not possible to modify the protrusion amount of each object of a stereoscopic image from only the left-and-right-eye formatted data that uses the parallax barrier method. However, the art that is disclosed in Patent Document 2, in the case of the left-and-right-eye formatted data being image data such as that obtained using for example a stereo camera, includes data of a format in which modification of the protrusion amount is possible (hereinbelow sometimes referred to as “modifiable data”) in 3D data and performs a synthesis process of the left-and-right-eye formatted data in which the protrusion amount is fixed, and this modifiable data. This process enables modification of the protrusion amount for a partial region of the stereoscopic image at the side of a terminal device. Besides data in which single-eye-formatted data has been converted to a stereoscopically displayable format, left-and-right-eye formatted data being data of a format in which the protrusion amount can be modified by modifying the horizontal direction relative distance of data corresponding to both eyes is included in the aforementioned modifiable data. In other words, in this related art, the protrusion amount of a partial region of a stereoscopic image is modified based on the modifiable data.
As other related art, technology is disclosed that can realize an operation feeling approximating an operation of a more realistic three-dimensional space by detecting the spatial position with a touch panel (for example, refer to Patent Document 3 and Patent Document 4).